/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */

package wx.xml.xalan.xpath.compiler;

/**
 * Like IntVector, but used only for the OpMap array.  Length of array
 * is kept in the m_lengthPos position of the array.  Only the required methods
 * are in included here.
 *
 * @xsl.usage internal
 */
public class OpMapVector {

    /**
     * Size of blocks to allocate
     */
    protected int m_blocksize;

    /**
     * Array of ints
     */
    protected int m_map[]; // IntStack is trying to see this directly

    /**
     * Position where size of array is kept
     */
    protected int m_lengthPos = 0;

    /**
     * Size of array
     */
    protected int m_mapSize;

    /**
     * Construct a OpMapVector, using the given block size.
     *
     * @param blocksize Size of block to allocate
     */
    public OpMapVector(int blocksize, int increaseSize, int lengthPos) {

        m_blocksize = increaseSize;
        m_mapSize = blocksize;
        m_lengthPos = lengthPos;
        m_map = new int[blocksize];
    }

    /**
     * Get the nth element.
     *
     * @param i index of object to get
     * @return object at given index
     */
    public final int elementAt(int i) {
        return m_map[i];
    }

    /**
     * Sets the component at the specified index of this vector to be the
     * specified object. The previous component at that position is discarded.
     * <p>
     * The index must be a value greater than or equal to 0 and less
     * than the current size of the vector.
     *
     * @param value object to set
     * @param index Index of where to set the object
     */
    public final void setElementAt(int value, int index) {
        if (index >= m_mapSize) {
            int oldSize = m_mapSize;

            m_mapSize += m_blocksize;

            int newMap[] = new int[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, oldSize);

            m_map = newMap;
        }

        m_map[index] = value;
    }


    /*
     * Reset the array to the supplied size.  No checking is done.
     *
     * @param size The size to trim to.
     */
    public final void setToSize(int size) {

        int newMap[] = new int[size];

        System.arraycopy(m_map, 0, newMap, 0, m_map[m_lengthPos]);

        m_mapSize = size;
        m_map = newMap;

    }

}
